package cn.itcast.springboot.conf;

import java.util.Collection;
import java.util.Iterator;

import org.springframework.security.access.AccessDecisionManager;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.authentication.InsufficientAuthenticationException;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;


public class MyAccessDecisionManager implements AccessDecisionManager {

	// decide 方法是判定是否拥有权限的决策方法，
	  //authentication 是释CustomUserService中循环添加到 GrantedAuthority 对象中的权限信息集合.
	  //object 包含客户端发起的请求的requset信息，可转换为 HttpServletRequest request = ((FilterInvocation) object).getHttpRequest();
	  //configAttributes 为MyInvocationSecurityMetadataSource的getAttributes(Object object)这个方法返回的结果，此方法是为了判定用户请求的url 是否在权限表中，如果在权限表中，则返回给 decide 方法，用来判定用户是否有此权限。如果不在权限表中则放行。
	    @Override
	    public void decide(Authentication authentication, Object object, Collection<ConfigAttribute> configAttributes) throws AccessDeniedException, InsufficientAuthenticationException {

	        if(null== configAttributes || configAttributes.size() <=0) {
	            return;
	        }
	        ConfigAttribute c;
	        String needRole;
	        for(Iterator<ConfigAttribute> iter = configAttributes.iterator(); iter.hasNext(); ) {
	            c = iter.next();
	            needRole = c.getAttribute();
	            for(GrantedAuthority ga : authentication.getAuthorities()) {//authentication 为在注释1 中循环添加到 GrantedAuthority 对象中的权限信息集合
	                if(needRole.trim().equals(ga.getAuthority())) {
	                    return;
	                }
	            }
	        }
	        throw new AccessDeniedException("no right");
	    }

	    @Override
	    public boolean supports(ConfigAttribute attribute) {
	        return true;
	    }

	    @Override
	    public boolean supports(Class<?> clazz) {
	        return true;
	    }

}
